extract models manager and related ownership from core (#16508)

## Summary
- split `models-manager` out of `core` and add `ModelsManagerConfig`
plus `Config::to_models_manager_config()` so model metadata paths stop
depending on `core::Config`
- move login-owned/auth-owned code out of `core` into `codex-login`,
move model provider config into `codex-model-provider-info`, move API
bridge mapping into `codex-api`, move protocol-owned types/impls into
`codex-protocol`, and move response debug helpers into a dedicated
`response-debug-context` crate
- move feedback tag emission into `codex-feedback`, relocate tests to
the crates that now own the code, and keep broad temporary re-exports so
this PR avoids a giant import-only rewrite

## Major moves and decisions
- created `codex-models-manager` as the owner for model
cache/catalog/config/model info logic, including the new
`ModelsManagerConfig` struct
- created `codex-model-provider-info` as the owner for provider config
parsing/defaults and kept temporary `codex-login`/`codex-core`
re-exports for old import paths
- moved `api_bridge` error mapping + `CoreAuthProvider` into
`codex-api`, while `codex-login::api_bridge` temporarily re-exports
those symbols and keeps the `auth_provider_from_auth` wrapper
- moved `auth_env_telemetry` and `provider_auth` ownership to
`codex-login`
- moved `CodexErr` ownership to `codex-protocol::error`, plus
`StreamOutput`, `bytes_to_string_smart`, and network policy helpers to
protocol-owned modules
- created `codex-response-debug-context` for
`extract_response_debug_context`, `telemetry_transport_error_message`,
and related response-debug plumbing instead of leaving that behavior in
`core`
- moved `FeedbackRequestTags`, `emit_feedback_request_tags`, and
`emit_feedback_request_tags_with_auth_env` to `codex-feedback`
- deferred removal of temporary re-exports and the mechanical import
rewrites to a stacked follow-up PR so this PR stays reviewable

## Test moves
- moved auth refresh coverage from `core/tests/suite/auth_refresh.rs` to
`login/tests/suite/auth_refresh.rs`
- moved text encoding coverage from
`core/tests/suite/text_encoding_fix.rs` to
`protocol/src/exec_output_tests.rs`
- moved model info override coverage from
`core/tests/suite/model_info_overrides.rs` to
`models-manager/src/model_info_overrides_tests.rs`

---------

Co-authored-by: Codex <noreply@openai.com>

codex-rs/core/src/codex.rs

@@ -570,7 +570,9 @@ impl Codex {
         // 1. config.base_instructions override
         // 2. conversation history => session_meta.base_instructions
         // 3. base_instructions for current model
-        let model_info = models_manager.get_model_info(model.as_str(), &config).await;
+        let model_info = models_manager
+            .get_model_info(model.as_str(), &config.to_models_manager_config())
+            .await;
         let base_instructions = config
             .base_instructions
             .clone()
@@ -903,7 +905,9 @@ impl TurnContext {
     pub(crate) async fn with_model(&self, model: String, models_manager: &ModelsManager) -> Self {
         let mut config = (*self.config).clone();
         config.model = Some(model.clone());
-        let model_info = models_manager.get_model_info(model.as_str(), &config).await;
+        let model_info = models_manager
+            .get_model_info(model.as_str(), &config.to_models_manager_config())
+            .await;
         let truncation_policy = model_info.truncation_policy.into();
         let supported_reasoning_levels = model_info
             .supported_reasoning_levels
@@ -2466,7 +2470,7 @@ impl Session {
             .models_manager
             .get_model_info(
                 session_configuration.collaboration_mode.model(),
-                &per_turn_config,
+                &per_turn_config.to_models_manager_config(),
             )
             .await;
         let plugin_outcome = self
@@ -5504,7 +5508,7 @@ async fn spawn_review_thread(
     let review_model_info = sess
         .services
         .models_manager
-        .get_model_info(&model, &config)
+        .get_model_info(&model, &config.to_models_manager_config())
         .await;
     // For reviews, disable web_search and view_image regardless of global settings.
     let mut review_features = sess.features.clone();